Add support for extensionless Python files for server

[dhruvmanila]

Summary

Closes: #12539

Test Plan

Screen.Recording.2024-09-11.at.11.32.32.mov

[github-actions]

ruff-ecosystem results

Linter (stable)

✅ ecosystem check detected no linter changes.

Linter (preview)

✅ ecosystem check detected no linter changes.

[MichaReiser]

Thanks.

Checking all recognized python files seems like a sensible thing to me. My only concern is that the LSP and CLI now disagree on the file that need checking.

[dhruvmanila]

Checking all recognized python files seems like a sensible thing to me. My only concern is that the LSP and CLI now disagree on the file that need checking.

That's true but this behavior seems reasonable from an editor perspective because the client provides us this information. This is also a regression from ruff-lsp which is resolved with this PR.